public class ZhaiZhiJie03
{
    public static void main(String[] args) {
        B1 b = new B1();
    }
}

abstract class A1
{
    public A1()
    {
        System.out.println("A1");
    }
    abstract void print();
}

class B1 extends A1
{
    public B1()
    {
        System.out.println("B1");
    }
    public void print()
    {
        System.out.println("haha");
    }
}